A model predicts that the world's populations will stop growing in 2050

Apr 04, 2013

Global population data spanning the years from 1900 to 2010 have enabled a research team from the Autonomous University of Madrid to predict that the number of people on Earth will stabilise around the middle of the century. The results, obtained with a model used by physicists, coincide with the UN's downward forecasts.

According to United Nations' estimates, the world population in 2100 will be within a range between 15.8 billion people according to the highest estimates –high fertility variant– and 6.2 billion according to the lowest –low fertility variant–, a figure that stands below the current 7 billion.

A mathematical model developed by a team from the Autonomous University of Madrid (UAM) and the CEU-San Pablo University, both from Spain, seems to confirm the lower estimate, in addition to a standstill and even a slight drop in the number of people on Earth by the mid-21st century.

The population prospects between 1950 and 2100 provided by the UN were used to conduct the study, published in the journal 'Simulation'. Mathematical equations which are used in scientific fields, such as condensed matter physics, were then applied to this data.

"This is a model that describes the evolution of a two-level system in which there is a probability of passing from one level to another," as explained to SINC by Félix F. Muñoz, UAM researcher and co-author of the project.

The team considered the Earth as a closed and finite system where the migration of people within the system has no impact and where the fundamental principle of the conservation of mass –biomass in this case– and energy is fulfilled.

"Within this general principle, the variables that limit the upper and lower zone of the system's two levels are the birth and mortality rates," Muñoz pointed out and recalled the change that occurred in the ratio between the two variables throughout the last century.

This is an estimated and projected world population according to different variants, 1950-2100 (billions). The model matches with the low fertility variant. Credit: UN

"We started with a general situation where both the birth rate and mortality rate were high, with slow growth favouring the former," he added, "but the mortality rate fell sharply in the second half of the 20th century as a result of advances in healthcare and increased life expectancy and it seemed that the population would grow a lot.

However, the past three decades have also seen a steep drop-off in the number of children being born worldwide."

The model's S-shaped sigmoid curve reflects this situation with an inflection point in the mid-1980s when the speed at which the population is growing starts to slow down until it stabilises around 2050.

The data also reflect the downward trend in the UN's series of prospects. "Overpopulation was a spectre in the 1960s and 70s but historically the UN's low fertility variant forecasts have been fulfilled," Muñoz highlighted.

As recently as 1992 it was predicted that there would be 7.17 billion people on Earth by 2010 instead of the actual 6.8 billion. In fact, the fertility rate has fallen by more than 40% since 1950.

"This work is another aspect to be taken into consideration in the debate, although we do not deal with the significant economic, demographic and political consequences that the stabilisation and ageing of the world population could entail," the researcher concluded.

More information: Julio A Gonzalo, Félix-Fernando Muñoz, David J Santos. "Using a rate equations approach to model World population trends". Simulation: Transactions of the Society for Modeling and Simulation International 89: 192-198, February 2013.

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This is assuming that pop growth is a result of wholly natural forces, and not at least in part the Product of demographic Planning and Engineering.

The future of what may be the only intelligent in existence, will not be left to chance. The world has been Managed for millenia. The fact that we are still here at all, and are poised to colonize other planets, is proof of this. Humans began stripping the earth in earnest after the advent of agriculture. Leaders saw what was being done and decided to take Action to endure the future of their descendants.

They began cooperating to divide the people up and set them against one another in creative and constructive Ways.Cont>

"There was a time when the countless tribes of men, though wide-dispersed, oppressed the surface of the deep-bosomed Earth, and Zeus saw it and had pity and in his wise heart resolved to relieve the all-nurturing Earth of men by causing the great struggle of the Ilian war, that the load of death might empty the world. And so the heroes were slain in Troy, and the plan of Zeus came to pass."http://www.popula...tations/

-And of course a very recent, very blatant indication of the Nature of this Engineering - the ONE BILLION ABORTIONS within the last century, and the hundreds of millions more pregnancies which never occurred, as the most significant Result of the systematic destruction during the world wars of the obsolete eurasian religionist cultures which would have prevented it from happening.

This can be no coincidence. Fully 1/5 of the worlds population and their defendants to 3 and 4 gens, were never born. By Design.

There's no question that there has to be an upper limit to the population and we will achieve it sooner or later. The problem is how we and nature maintain that limit. It won't be pretty for many if not most living at the limit because we will push that limit past easy sustainability.

Wont happen. I personally believe the populations will continue to grow until sustainability is long gone and we collapse. Remember, if you average out the lifespan of previous civilisations they do not last much beyond 380 years.. And that is fast approaching....

btb101: Your comment about civilization lifespans is true, but usually they fall for other reasons than lack of resources. Government corruption and civil insurrections are usually the top causes. The ancient Egyptians, Romans, Mongols, etc... did not collapse due to starvation or thirst. Neither did the Spanish, British or French Empires.

I agree that "civilization" will go beyond sustainability, but I think the last time we were beyond our sustainability was a long time ago when 90 % of humanity died off after the last supervolcano went off wiping out most plant and animal life.

-No disease has ever approached this SUSTAINED level of impact on pop growth.

Not to mention pregnancies prevented:

"the numbers of unintended pregnancies prevented byall U.S. publicly funded family planning clinics in 2004, nationally (1.4 million pregnancies)"

"In 2007, contraceptives offered by [Californias] Family PACT program averted an estimated 286,700 unintended pregnancies which would have included 122,000 abortions, according to data she provided."http://www.livesc...ies.html

Traditionally it has ultimately been war which has limited pop growth. Tribes grew until they came into conflict over resources. Tribal warfare was, and is, endemic.

Tribes whose members were better able to cooperate, plan, use technology, and anticipate an enemys actions, would be expected to prevail in conflict.

The winners secured repro rights over large numbers of females. As a result the human brain grew to an unsustainable size. The body changed to facilitate carrying and throwing weapons, and running long distances (to outflank enemies).

Each new advance in technology which reduced natural attritive elements would only make tribes grow faster, and increase the frequency and intensity of war.http://rechten.el...RID2.pdf

-We are a product of war because of our propensity to overpopulate. We only now have an alternative. Family planning.